JPH06505308A - A metal wire comprising a cold-rolled and tempered steel matrix and coating with a martensitic structure, and a method for producing this wire. - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Cold rolled and tempered steel matrix and coating with martensitic structure Metal wire rod containing, and manufacturing method of this wire rod The present invention relates to steel wires and methods of manufacturing these wires. These wire rods products of plastic or rubber materials, especially tubes, belts, sheets, ties. Used for reinforcing the outer skin.

This type of wire currently in common use consists of steel containing at least 0.6% carbon. This steel has a cold-rolled pearlite structure. Breaks in these wires The breaking resistance is approximately 2800 MPa (megapascal), and its diameter is generally 0.15 to 0. ．． 35, and its elongation at break is between 0.4 and 2%. These wires are 5 – Manufactured by drawing a starting wire called “processed wire” with a diameter on the order of 6 m. The structure of this processed wire is generally pearlite containing a high content of 72% or more. -It is a hard structure consisting of ferrite and ferrite. When manufacturing this wire, the first assembly This wire drawing process can be reduced in order to carry out one or more heat treatments to regenerate the weave. Both are interrupted once. In order for the final wire drawing process to be carried out accurately after the final heat treatment. requires a deposit of an alloy, for example brass, on the wire.

This method has the following problems.

- The raw materials are expensive due to their relatively high carbon content.

- It is not easy to change parameters. In particular, there are strict limits on the diameter of processed wire and the final diameter. This method lacks flexibility because the

The hardness of the processed wire is high due to its structure with a high pearlite content, making it difficult to draw the wire before heat treatment. Therefore, the deformation rate ε of this wire drawing process is naturally 3 or less. On the other hand, this wire drawing The speed is low and there is a possibility that the wire may break during this process.

The operation of depositing an alloy, e.g. brass, is a necessary step in this process; It cannot be combined with a preceding heat treatment operation.

On the other hand, the fracture resistance and fracture ductility of the wire itself are often insufficient, and the Due to its high hardness, it is subject to significant damage as a result of wire drawing before heat treatment.

The gist of the present invention is to provide a cold-rolled and tempered steel wire of a metal alloy. The material steel has a tempered non-pearlitic structure and has a known tempered pearlite structure. It has at least the same breaking resistance and breaking elongation as steel wire rods, and is better than known wire rods. An object of the present invention is to provide a steel wire rod that is less damaged by wire drawing.

Another object of the present invention is to provide a method for manufacturing this wire that does not exhibit the above-mentioned problems. It is to serve.

The metal wire according to the invention has a substrate and a coating and exhibits the following properties: b) comprising a steel matrix with a carbon content of at least 0.05% and at most 0.6%; 口）This steel contains more than 90% cold rolled and tempered martensite. (c) the substrate is coated with a metal alloy other than steel, and (2) the substrate is coated directly with the wire. The diameter is equal to the minimum 0.10m+a and the maximum 0.40■, e) The breaking resistance of the wire is at least equal to 2800 MPa, f) The elongation at break of the wire is at least equal to 0.4%.

The method according to the invention for producing this wire of coated steel is characterized by the following steps.

b) It has a carbon content of minimum 0.05% and maximum 0.6%, and a carbon content of 28% to 96%. A processed steel wire containing ferrite and 72% to 4% pearlite is cold-rolled. rolling, and the deformation rate ε of the cold rolling is at least 3; (1) Stop cold rolling, perform quenching treatment on the cold rolled wire rod, and The quenching process involves heating the wire above the AC3 transformation point to uniformly austenize it. After that, the wire is rapidly cooled to below the martensitic transformation end point MF. and the cooling rate is such that a structure containing 90% or more martensite is obtained. equal to at least 150°C/sec; C) Next, at least two metals that can form an alloy by diffusion are placed on the wire. forming a steel-based coating; 2) Next, heat the wire to a temperature of minimum 0.37F and maximum 0.5TF, and by diffusion Forms an alloy of the deposited metal and, for steel, tempered marten of 90% or more. A structure containing sites is formed, and TF is the melting point of the steel expressed in Kelvin temperature. stages and e) Next, cooling the wire to a temperature of 0.3TF or less, f) Next, cold rolling is performed on the wire rod, and the wire rod temperature during cold rolling is 0.3 7F or less, and the deformation rate ε of this cold rolling is at least 1.

The invention also relates to an assembly comprising at least one wire according to the invention. be.

The invention also provides at least a portion of the wire or assembly according to the above definition. Reinforced products such as tubes, belts, seats, tire skins.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings, but the present invention is limited thereto. It is not something that will be done.

In the attached figure, FIG. 1 is a diagram showing the structure of the steel of the wire rod before heat treatment when carrying out the method of the present invention, Figure 2 shows the structure of the steel wire after quenching heat treatment when carrying out the method of the present invention. figure, FIG. 3 is a diagram showing the structure of the steel of the wire rod after brass plating when carrying out the method of the present invention, FIG. 4 is a diagram showing the structure of the steel of the wire rod according to the present invention.

In the following, all percentages are by weight and also refer to break resistance and break elongation. The measurements were carried out on an AFNORNFA 03-151.

By definition, the deformation rate ε of cold rolling treatment is expressed by the formula ε = Ln (So/St), Here, Ln is the natural logarithm, SO is the cutting area of the wire before cold rolling, and Sf is this cold rolling. This is the cross-sectional area of the wire after inter-rolling.

The purpose of the following examples is to demonstrate the manufacturing method and properties of three wires according to the invention. Ru.

In these examples, a non-cold rolled processed wire with a diameter of 5.5 m was used. do. This processed wire rod is made of steel with the following composition.

Carbon content ・0.4% -Manganese content = 0.5% -Silicon content 20.2% -Phosphorus content: 0.015% -Sulfur content: 0.02% -Aluminum content: 0.015% -Nitrogen content: 0.005% -Chromium content: 0.05% -Nickel content: 0.10% -Copper content: 0.10% -Molybdenum content: 0.01% -Pro-eutectoid ferrite content: 53% 1 Perlite content = 47% Copper steel melting point, TF: 1795 χ - Martensitic transformation stability point, MF: 150℃ - Fracture resistance, Rm near 00MP a -Elongation at break, Ar: 17% Using this processed wire rod, three wire rods are manufactured as in the following example.

Example 1 The processed wire is descaled, wire drawing soap, such as borax, is applied to the wire and dried. Perform wire drawing to obtain a wire rod with a diameter of 1.1 cm. This results in a deformation rate ε slightly higher than 3.2. handle.

Wire drawing is easily carried out due to the relatively ductile texture of the processed wire. - For example, cold The unrolled 0.7% carbon steel has a fracture resistance Rm of about 900 MPa and a It shows a breaking elongation Ar of 8%. That is, this steel has significantly low ductility.

Also - as an example, this wire drawing is carried out at temperatures below 0.3 TF, which is not possible. It's not necessary, but it's for the sake of simplicity. This wire drawing temperature is equivalent to or higher than 0.3TF. You can do it above.

FIG. 1 is a cross-sectional view of part 1 of the structure of the wire obtained in this manner. this organization consists of an elongated cementite block 2 and an elongated ferrite block 3, The major dimensions of these blocks are oriented in the drawing direction.

This wire is subjected to the following heat treatment.

- The wire is heated to 950°C by convection in a muffle furnace, i.e. above the transformation point AC3. and held at this temperature for 30 seconds to obtain a uniform austenite structure.

- The wire is then heated to 75°C in a gas ring generated by a turbine, i.e. In other words, it takes 3.5 seconds to reach below the martensite transformation stable point MF (martensite stability) It is cooled within a few seconds to obtain a structure containing more than 90% martensite laths.

FIG. 2 is a cross-sectional view of a part 4 of the tissue obtained in this way, and shows the maltite described above. The last of the sights is indicated by 5.

Next, the wire is degreased. Next, the wire is coated with copper by electrolysis at room temperature, and then zinc is coated. Cover. Next, this wire was heated to 540°C (813°K) for 2 hours due to the Joule effect. Heat treated for 5 seconds and then cooled the wire to room temperature (20°C or 293″K) .

This heat treatment results in a brass coating due to the diffusion of copper and zinc, and also for steel A structure containing 90% or more of tempered martensite is obtained. This brass layer The thickness of the wire is thin (on the order of micrometers) and can be ignored relative to the wire diameter.

FIG. 3 is a cross-sectional view of part 6 of the structure of the wire obtained in this manner. this organization contains carbon precipitates 7 virtually uniformly distributed within a matrix 8 of ferritic type. child The structure is obtained by the heat treatment described above and preserved upon cooling to room temperature. precipitation Item 7 generally has a particle size of at least 0.005 μm (micrometer) and at most 1 μm. do.

This wire is then subjected to wet drawing to obtain a final diameter of 0.21. This is actually Corresponds to ε=3.4. During this wire drawing, the wire temperature is naturally below 0.37F. be.

The thickness of the brass layer of the wire drawn in this way is extremely thin, 1/10 micrometer. It's an order of magnitude.

FIG. 4 is a longitudinal cross-sectional view of a portion 9 of the steel wire according to the present invention obtained in this manner. Ru. This part 9 shows a cold-rolled and tempered martensitic structure, and this The weave consists of elongated carbides 10, which are practically parallel to each other and whose The maximum dimension is in the axial direction of the wire, that is, in the drawing direction indicated by arrow oriented in the direction. These carbides] 0 are arranged in the cold-rolled substrate 11 has been done.

This wire according to the present invention has a breaking resistance of 3000 MPa and a breaking elongation of 0.7%. have people.

Example 2 The processed wire is descaled, wire drawing soap, such as borax, is applied to the wire and dried. Perform wire drawing to obtain a wire rod with a diameter of 0.9 m. This results in a deformation rate ε slightly higher than 3.6. handle. The tissue obtained is similar to that shown in FIG.

Therefore, the following heat treatment is performed on this wire.

Due to the Joule effect, the wire is heated to 1000℃ in 3 seconds, that is, the transformation point AC3 or higher. Heating to a certain temperature yields a uniform austenitic structure. Next, oil the wire within 3 seconds. Cooled in a bath to a temperature of 100°C, that is, a temperature below the stable transformation point MP, and heated to 90°C. % or more of martensite laths. The obtained wire structure is shown in Figure 2. vinegar.

Next, the wire is degreased. Next, the wire is coated with copper by electrolysis at room temperature, and then zinc is coated. Cover. Next, this wire was heated at 540°C (813°C) for 2.5 seconds using the Joule effect. χ), and then the wire is cooled to room temperature. These treatments were similar to those in Example 1. It is similar.

The structure of this brass-treated wire is similar to that shown in FIG. There, the wire is wet-processed. The wire is drawn to obtain a final diameter of 0.1'1 m. This actually corresponds to ε=3.3 do.

The wire temperature during this wire drawing is 0.3 TF or less.

The wire rod steel of the present invention thus obtained has a structure similar to that shown in FIG.

This wire has a breaking resistance of 2850 MPa and an elongation at break equal to 1%. do.

Example 3 A wire rod with a diameter of 1.1 days obtained by drawing a processed wire rod in the same manner as in Example 1 was Heat it to 1000℃ for 3 seconds using the electric current to a temperature above the transformation point AC3, and then - Obtains a stenite structure.

Next, this wire is heated to 100℃ in a gas ring generated by a turbine. That is, by cooling to a temperature below the stable transformation point MF in 3 seconds or less, martensa of 90% or more Obtain tissue containing itolas.

The wire is then coated with copper by electrolytic method, then coated with zinc, and then joule-coated for 5 seconds. The fruit is heat treated at 500℃ (773χ). Next, this brass-treated wire is heated to room temperature. and wet wire drawing to a diameter of 0.17 m at a temperature of 0.37 F or less. this is real In practice, this corresponds to ε=3.7. This wire according to the present invention has a power of 3200 MPa. It has break resistance and elongation at break of 0.6%.

The intermediate and final structures are similar to those described above.

The present invention has the following advantages.

Starting from processed wire with low carbon content, the cost is low.

High flexibility in selection of wire diameter. i.e. significantly larger than, for example, 6 m. Processed wire rods with diameters can be used, which reduces costs and is extremely Wire rods of various diameters can be manufactured.

- Since wire drawing before heat treatment is relatively easy, the deformation rate ε of this wire drawing is 3 or more. I can do things. On the other hand, this wire drawing can be carried out at high speed. Finally, check for wire breakage. The frequency and frequency of nozzle replacement is reduced. This further reduces costs.

A diffusion treatment to produce an alloy is carried out simultaneously with tempering of the wire. this is, Eliminates the need for additional diffusion treatment, and allows the entire wire rod to be processed from processed wire to finished wire. Reduce manufacturing costs by enabling targeted line production.

1. The wire rod of the present invention has a breaking resistance value and a breaking elongation value that are at least equivalent to known wire rods. give. This is demonstrated by a breaking energy at least equivalent to known wires. Ru.

One of the wire rods of the present invention is less damaged during wire drawing before heat treatment.

The wire rod of the present invention has a lower carbon content, so it has better corrosion resistance than known wire rods. ing.

When performing hardening treatment from homogeneous austenite, the transformation point from AC3 to MF or higher According to the invention, the cooling rate is at least 150° C./sec. is equal, so before reaching the temperature corresponding to the martensitic transformation start point (MS) Since less than 10% of the homogeneous austenite is transformed, at the end of this quenching process, The structure contains more than 90% martensite, and therefore the structure as a whole is martensite. It can be considered as tensite. Preferably, the martensa obtained after quenching The fibers have a lath-like texture as described in the previous examples.

Preferably, the steel of the wire according to the invention, and therefore the processed wire, has a minimum content of 0.2% and a maximum of 0.2%. It has a carbon content of 5%.

Preferably, the steel of the wire according to the invention, and therefore the raw processed wire, has the following composition: 20.3%≦Mn≦0.6%; 0.1%≦Si≦0.3%; P≦0.02%; S≦0.02%, AI≦0.02%; N≦0.006%.

Preferably, the steel of the wire according to the present invention, and therefore the processed wire, has the following composition: Cr≦0.06%; Ni≦0.15%; Cu≦0.15%.

Preferably, the method according to the invention has at least one of the following properties:

The one-start processed wire has a pro-eutectoid ferrite content of at least 41% and at most 78%, and at least 2 2% and a maximum pearlite content of 59%.

The deformation rate ε during cold rolling before heat treatment is equal to a minimum of 3.2 and a maximum of 6.

The deformation rate ε during the final cold rolling after the first heat treatment is equal to a minimum of 3 and a maximum of 5.

- The quenching heat treatment is carried out with a cooling rate of at least 250° C./sec.

The cold rolling of the wire rod in the above embodiment is carried out by wire drawing, but the cold rolling process It is also possible to carry out a rolling process in combination with other techniques, e.g. wire drawing. It is also possible to administer. Of course, the present invention is not limited to the above-mentioned embodiments; For example, the invention provides an alloy of two or more metals other than brass, such as copper- When using ternary alloys of zinc-nickel, copper-zinc-cobalt, and copper-zinc-tin, In short, the metal used must be diffused at a temperature of at least 0°3TF and at a maximum of 0.57F. The reason is that alloys can be formed by

international search report international search report Continuation of front page (72) Inventor Serres, Raoul France Sayla, Abounus, Wilson, 18

Claims (20)

[Claims] 1. It has a substrate and a coating, and has the following characteristics: a) minimum 0.05% and maximum 0.6% charcoal; comprising a matrix of steel having an elemental content; b) This steel contains more than 90% cold rolled and tempered martinsite. (c) the substrate is coated with a metal alloy other than steel, and (d) the substrate is coated with a direct wire rod. The diameter is equal to a minimum of 0.10 mm and a maximum of 0.40 mm, e) The breaking resistance of the wire is at least equal to 2800 MPa, f) A metal wire characterized in that the elongation at break of the wire is at least equal to 0.4%. 2. Claims characterized in that the carbon content is at least 0.2% and at most 0.5%. 1. The wire rod according to 1. 3. Either claim 1 or 2, wherein the steel satisfies the following relationship: Metal wire rod as described in: 0.3%≦Mn≦0.6%; 0.1%≦Si≦0.3%; P ≦0.02%; S≦0.02%; Al≦0.02%; N≦0.006%. 4. The metal wire according to claim 3, wherein the steel satisfies the following relationship: Cr≦0.06%; Ni≦0.15%; Cu≦0.15%. 5. 5. The metal alloy according to claim 1, wherein the metal alloy is brass. wire. 6. b) It has a carbon content of minimum 0.05% and maximum 0.6%, and ranges from 28% to 96%. Processed steel wire containing pro-eutectoid ferrite and 72% to 4% pearlite. cold rolling, and the deformation rate ε of the cold rolling is at least 3; b) Stop cold rolling, perform quenching treatment on the cold rolled wire rod, and The quenching process involves heating the wire above the AC3 transformation point to uniformly austenize it. After that, the wire is rapidly cooled to below the multisite transformation end point MF. , and the cooling rate is such that a structure containing 90% or more of martinsite is obtained. equal to at least 150°C/sec; C) Next, at least two metals that can form an alloy by diffusion are placed on the wire. forming a steel-based coating; d) Next, heat the wire to a temperature of minimum 0.3 TF and maximum 0.5 TF, and by diffusion Forms an alloy of the deposited metal and, for steel, tempered martin of 90% or more. A structure containing sites is formed, and TF is the melting point of the steel expressed in Kelvin temperature. stages and e) Next, cooling the wire to a temperature of 0.3TF or less, f) Next, cold rolling is performed on the wire rod, and the wire rod temperature during cold rolling is 0.3 TF or less, and the deformation rate ε of this cold rolling is at least 1. The method for manufacturing a wire rod according to any one of claims 1 to 5. 7. The starting processed wire has a carbon content of at least 0.2% and 0.5% for age. 7. The method according to claim 6, characterized in that: 8. Either claim 6 or 7, wherein the steel satisfies the following relationship: The method described in: 0.3%≦Mn≦0.6%; 0.1%≦Si≦0.3%; P≦0 ．． 02%; S≦0.02%; Al≦0.02%; N≦0.006%. 9. The method according to claim 8, characterized in that the steel satisfies the following relationship: Cr ≦0.06%; Ni≦0.15%; Cu≦0.15%. 10. The starting processed wire has a pro-eutectoid ferrite content of at least 41% and at most 78%. 6. Pearlite content as low as 22% and as high as 59%. 10. The method according to any one of 1 to 9. 11. The deformation rate ε during cold rolling before heat treatment is equal to a minimum of 3.2 and a maximum of 6. The method according to any one of claims 6 to 10, characterized in that: 12. The deformation rate ε during final cold rolling after heat treatment is equal to a minimum of 3 and a maximum of 5. A method according to any one of claims 6 to 11, characterized in that: 13. The adhesion treatment performed on the wire after quenching heat treatment is the adhesion of copper and zinc. 13. A method according to any of claims 6 to 12, characterized in that: 14. at least one cold rolling process is performed at least partially by wire drawing; 14. A method according to any one of claims 6 to 13, characterized in that: 15. The quenching heat treatment is performed at a cooling rate of at least 250°C/sec. The method according to any one of claims 6 to 14, characterized in that: 16. Quenching heat treatment lines the structure containing 90% or more lath martensite. 16. A method according to claim 15, characterized in that the method is applied to a material. 17. An assembly containing at least one wire according to any of claims 1 to 5. body. 18. Reinforced by at least one wire rod according to any one of claims 1 to 5. products. 19. Article reinforced with at least one assembly according to claim 17. 20. Claim 18 or 19, characterized in that it is a tire outer skin. Products listed.